head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Competitive PvP
Open-zone gunfights where aim, ambush prediction and gear economy all matter.

Execution · Competitive PvP
Artillery aim and turn planning against human opponents on destructible terrain.
Stalcraft: X leans Execution (Competitive PvP); Worms Clan Wars leans Execution (Competitive PvP).
Stalcraft: X leans a little harder on execution, though the gap is small.
Stalcraft: X
Gunfights against other stalkers reward raw aim and movement
Worms Clan Wars
Grenade arcs and ninja-rope control decide turns
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Stalcraft: X
Open-zone PvP means predicting ambushes from adapting humans
Worms Clan Wars
Anticipating human opponents' target priorities matters in clan play
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Stalcraft: X
Anomalies, artifact spawns and who you meet inject randomness
Worms Clan Wars
Crate drops and terrain destruction add swing
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Stalcraft: X
Gear economy, artifact builds and route knowledge compound
Worms Clan Wars
Weapon economy and positioning plans reward forethought
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.